Low-power-consumption audio/video recording and communication doorbell

ABSTRACT

An audio/video (A/V) recording and communication doorbell, including a camera, a speaker, a microphone, a power manager, a battery, an AC/DC rectifier, and a DC/DC converter. The doorbell is configured for connection to an external AC power source through the AC/DC rectifier and the DC/DC converter. The power manager is configured to draw power, up to a threshold power, from the AC power source and to draw supplemental power from the battery such that the power drawn from the AC power source never exceeds the threshold power. The present A/V recording and communication doorbell can thus be connected to an existing household AC power supply and an existing doorbell signaling device without causing inadvertent sounding of the signaling device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/374,636 filed Apr. 3, 2019, which is a continuation of application Ser. No. 15/729,644, filed on Oct. 10, 2017, now U.S. Pat. No. 10,270,971, issued Apr. 23, 2019, which is a continuation of application Ser. No. 15/459,087, filed on Mar. 15, 2017, now U.S. Pat. No. 9,819,867, issued on Nov. 14, 2017, which claims priority to provisional application Ser. No. 62/308,746, filed on Mar. 15, 2016. The entire contents of the priority applications are hereby incorporated by reference as if fully set forth.

TECHNICAL FIELD

The present embodiments relate to audio/video (A/V) recording and communication devices, including A/V recording and communication doorbell systems. In particular, the present embodiments relate to improvements in the functionality of A/V recording and communication devices that enhance the streaming and storing of video recorded by such devices.

BACKGROUND

Home safety is a concern for many homeowners and renters. Those seeking to protect or monitor their homes often wish to have video and audio communications with visitors, for example, those visiting an external door or entryway. Audio/Video (A/V) recording and communication doorbell systems provide this functionality, and can also aid in crime detection and prevention. For example, audio and/or video captured by an A/V recording and communication doorbell can be uploaded to the cloud and recorded on a remote server. Subsequent review of the A/V footage can aid law enforcement in capturing perpetrators of home burglaries and other crimes. Further, the presence of an A/V recording and communication doorbell at the entrance to a home acts as a powerful deterrent against would-be burglars.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments of the present low-power-consumption audio/video (A/V) recording and communication doorbell now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious low-power-consumption A/V recording and communication doorbell shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts:

FIG. 1 is a functional block diagram illustrating an A/V recording and communication doorbell system according to the present embodiments;

FIG. 2 is a flowchart illustrating a process for streaming and storing A/V content from an A/V recording and communication doorbell system according to various aspects of the present disclosure;

FIG. 3 is a functional block diagram illustrating an embodiment of an A/V recording and communication doorbell system according to the present disclosure;

FIG. 4 is a front perspective view of an embodiment of an A/V recording and communication doorbell according to the present disclosure;

FIG. 5 is a rear perspective view of the A/V recording and communication doorbell of FIG. 4;

FIG. 6 is a partially exploded front perspective view of the A/V recording and communication doorbell of FIG. 4 showing the cover removed;

FIGS. 7, 8, and 9 are front perspective views of various internal components of the A/V recording and communication doorbell of FIG. 4;

FIG. 7A is a front perspective view of another embodiment of an infrared (IR) light-emitting diode (LED) printed circuit board (PCB) according to various aspects of the present disclosure;

FIG. 10 is a right-side cross-sectional view of the A/V recording and communication doorbell of FIG. 4 taken through the line 9-9 in FIG. 4;

FIGS. 11-13 are rear perspective views of various internal components of the A/V recording and communication doorbell of FIG. 4;

FIG. 14 is a flowchart illustrating a process according to various aspects of the present disclosure;

FIG. 15 is a functional block diagram illustrating an embodiment of a shunt according to the present disclosure;

FIGS. 16 and 17 are circuit diagrams illustrating embodiments of first and second comparator circuits, respectively, of the shunt of FIG. 15;

FIGS. 18 and 19 are waveform diagrams for the first comparator circuit of FIG. 16;

FIGS. 20 and 21 are waveform diagrams for the second comparator circuit of FIG. 17;

FIGS. 22 and 23 are flowcharts illustrating processes according to various aspects of the present disclosure;

FIG. 24 is a schematic diagram of a technique for creating intrusion zones according to various aspects of the present disclosure;

FIG. 25 is a functional block diagram of a client device on which the present embodiments may be implemented according to various aspects of the present disclosure; and

FIG. 26 is a functional block diagram of a general-purpose computing system on which the present embodiments may be implemented according to various aspects of present disclosure.

DETAILED DESCRIPTION

The various embodiments of the present low-power-consumption audio/video (A/V) recording and communication doorbell have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments as expressed by the claims that follow, their more prominent features now will be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of the present embodiments provide the advantages described herein.

One aspect of the present embodiments includes the realization that in current audio/video (A/V) recording and communication doorbell systems other than the present embodiments, it is difficult if not impossible to connect the A/V recording and communication doorbell to the existing household AC power supply (may also be referred to as AC mains), because the A/V recording and communication doorbell draws an amount of power from the AC power supply that is above the threshold necessary for causing the signaling device to sound. The A/V recording and communication doorbell thus causes frequent inadvertent sounding of the signaling device, which is not only bothersome to the home's occupant(s), but also undermines the usefulness of the doorbell. The present embodiments solve this problem by limiting the power consumption of the A/V recording and communication doorbell to an amount that is below the threshold necessary for causing the signaling device to sound. The present A/V recording and communication doorbell can thus be connected to the existing household AC power supply and the existing signaling device without causing inadvertent sounding of the signaling device.

The following detailed description describes the present embodiments with reference to the drawings. In the drawings, reference numbers label elements of the present embodiments. These reference numbers are reproduced below in connection with the discussion of the corresponding drawing features.

The embodiments of the present low-power-consumption audio/video (A/V) recording and communication doorbell are described below with reference to the figures. These figures, and their written descriptions, indicate that certain components of the apparatus are formed integrally, and certain other components are formed as separate pieces. Those of ordinary skill in the art will appreciate that components shown and described herein as being formed integrally may in alternative embodiments be formed as separate pieces. Those of ordinary skill in the art will further appreciate that components shown and described herein as being formed as separate pieces may in alternative embodiments be formed integrally. Further, as used herein the term integral describes a single unitary piece.

With reference to FIG. 1, the present embodiments include an audio/video (A/V) recording and communication doorbell 100. The A/V recording and communication doorbell 100 is typically located near the entrance to a structure (not shown), such as a dwelling, a business, a storage facility, etc. The A/V recording and communication doorbell 100 includes a camera 102, a microphone 104, and a speaker 106. The camera 102 may comprise, for example, a high definition (HD) video camera, such as one capable of capturing video images at an image display resolution of 720p, or 1080p, or any other image display resolution, including image display resolutions of better than 1080p. While not shown, the A/V recording and communication doorbell 100 may also include other hardware and/or components, such as a housing, one or more motion sensors (and/or other types of sensors), a button, etc. The A/V recording and communication doorbell 100 may further include similar componentry and/or functionality as the wireless communication doorbells described in US Patent Application Publication Nos. 2015/0022620 (application Ser. No. 14/499,828) and 2015/0022618 (application Ser. No. 14/334,922), both of which are incorporated herein by reference in their entireties as if fully set forth.

With further reference to FIG. 1, the A/V recording and communication device 100 communicates with a user's network 110, which may be for example a wired and/or wireless network. If the user's network 110 is wireless, or includes a wireless component, the network 110 may be a Wi-Fi network compatible with the IEEE 802.11 standard and/or other wireless communication standard(s). The user's network 110 is connected to another network 112, which may comprise, for example, the Internet and/or a public switched telephone network (PSTN). As described below, the A/V recording and communication doorbell 100 may communicate with a user's client device 114 via the user's network 110 and the network 112 (Internet/PSTN). The user's client device 114 may comprise, for example, a mobile telephone (may also be referred to as a cellular telephone), such as a smartphone, a personal digital assistant (PDA), or another communication device. The user's client device 114 comprises a display (not shown) and related components capable of displaying streaming and/or recorded video images. The user's client device 114 may also comprise a speaker and related components capable of broadcasting streaming and/or recorded audio, and may also comprise a microphone. The A/V recording and communication doorbell 100 may also communicate with one or more remote storage device(s) 116 (may be referred to interchangeably as “cloud storage device(s)”), one or more servers 118, and/or a backend API (application programming interface) 120 via the user's network 110 and the network 112 (Internet/PSTN). While FIG. 1 illustrates the storage device 116, the server 118, and the backend API 120 as components separate from the network 112, it is to be understood that the storage device 116, the server 118, and/or the backend API 120 may be considered to be components of the network 112.

The network 112 may be any wireless network or any wired network, or a combination thereof, configured to operatively couple the above mentioned modules, devices, and systems as shown in FIG. 1. For example, the network 112 may include one or more of the following: a PSTN (public switched telephone network), the Internet, a local intranet, a PAN (Personal Area Network), a LAN (Local Area Network), a WAN (Wide Area Network), a MAN (Metropolitan Area Network), a virtual private network (VPN), a storage area network (SAN), a frame relay connection, an Advanced Intelligent Network (AIN) connection, a synchronous optical network (SONET) connection, a digital T1, T3, E1 or E3 line, a Digital Data Service (DDS) connection, a DSL (Digital Subscriber Line) connection, an Ethernet connection, an ISDN (Integrated Services Digital Network) line, a dial-up port such as a V.90, V.34, or V.34bis analog modem connection, a cable modem, an ATM (Asynchronous Transfer Mode) connection, or an FDDI (Fiber Distributed Data Interface) or CDDI (Copper Distributed Data Interface) connection. Furthermore, communications may also include links to any of a variety of wireless networks, including WAP (Wireless Application Protocol), GPRS (General Packet Radio Service), GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access), and/or OFDMA (Orthogonal Frequency Division Multiple Access) cellular phone networks, GPS, CDPD (cellular digital packet data), RIM (Research in Motion, Limited) duplex paging network, Bluetooth radio, or an IEEE 802.11-based radio frequency network. The network can further include or interface with any one or more of the following: RS-232 serial connection, IEEE-1394 (Firewire) connection, Fibre Channel connection, IrDA (infrared) port, SCSI (Small Computer Systems Interface) connection, USB (Universal Serial Bus) connection, or other wired or wireless, digital or analog, interface or connection, mesh or Digi® networking.

According to one or more aspects of the present embodiments, when a person (may be referred to interchangeably as “visitor”) arrives at the A/V recording and communication doorbell 100, the A/V recording and communication doorbell 100 detects the visitor's presence and begins capturing video images within a field of view of the camera 102. The A/V recording and communication doorbell 100 may also capture audio through the microphone 104. The A/V recording and communication doorbell 100 may detect the visitor's presence by detecting motion using the camera 102 and/or a motion sensor, and/or by detecting that the visitor has depressed the button on the A/V recording and communication doorbell 100.

In response to the detection of the visitor, the A/V recording and communication doorbell 100 sends an alert to the user's client device 114 (FIG. 1) via the user's network 110 and the network 112. The A/V recording and communication doorbell 100 also sends streaming video, and may also send streaming audio, to the user's client device 114. If the user answers the alert, two-way audio communication may then occur between the visitor and the user through the A/V recording and communication doorbell 100 and the user's client device 114. The user may view the visitor throughout the duration of the call, but the visitor cannot see the user (unless the A/V recording and communication doorbell 100 includes a display, which it may in some embodiments).

The video images captured by the camera 102 of the A/V recording and communication doorbell 100 (and the audio captured by the microphone 104) may be uploaded to the cloud and recorded on the remote storage device 116 (FIG. 1). In some embodiments, the video and/or audio may be recorded on the remote storage device 116 even if the user chooses to ignore the alert sent to his or her client device 114.

With further reference to FIG. 1, the system may further comprise a backend API 120 including one or more components. A backend API (application programming interface) may comprise, for example, a server (e.g. a real server, or a virtual machine, or a machine running in a cloud infrastructure as a service), or multiple servers networked together, exposing at least one API to client(s) accessing it. These servers may include components such as application servers (e.g. software servers), depending upon what other components are included, such as a caching layer, or database layers, or other components. A backend API may, for example, comprise many such applications, each of which communicate with one another using their public APIs. In some embodiments, the API backend may hold the bulk of the user data and offer the user management capabilities, leaving the clients to have very limited state.

The backend API 120 illustrated FIG. 1 may include one or more APIs. An API is a set of routines, protocols, and tools for building software and applications. An API expresses a software component in terms of its operations, inputs, outputs, and underlying types, defining functionalities that are independent of their respective implementations, which allows definitions and implementations to vary without compromising the interface. Advantageously, an API may provide a programmer with access to an application's functionality without the programmer needing to modify the application itself, or even understand how the application works. An API may be for a web-based system, an operating system, or a database system, and it provides facilities to develop applications for that system using a given programming language. In addition to accessing databases or computer hardware like hard disk drives or video cards, an API can ease the work of programming GUI components. For example, an API can facilitate integration of new features into existing applications (a so-called “plug-in API”). An API can also assist otherwise distinct applications with sharing data, which can help to integrate and enhance the functionalities of the applications.

The backend API 120 illustrated in FIG. 1 may further include one or more services (also referred to as network services). A network service is an application that provides data storage, manipulation, presentation, communication, and/or other capability. Network services are often implemented using a client-server architecture based on application-layer network protocols. Each service may be provided by a server component running on one or more computers (such as a dedicated server computer offering multiple services) and accessed via a network by client components running on other devices. However, the client and server components can both be run on the same machine. Clients and servers may have a user interface, and sometimes other hardware associated with them.

FIG. 2 is a flowchart illustrating a process for streaming and storing A/V content from an A/V recording and communication doorbell system according to various aspects of the present disclosure. At block B200, the A/V recording and communication doorbell 100 detects the visitor's presence and begins capturing video images within a field of view of the camera 102. The A/V recording and communication doorbell 100 may also capture audio through the microphone 104. As described above, the A/V recording and communication doorbell 100 may detect the visitor's presence by detecting motion using the camera 102 and/or a motion sensor, and/or by detecting that the visitor has depressed the button on the A/V recording and communication doorbell 100.

At block B202, a communication module of the A/V recording and communication doorbell 100 sends a request, via the user's network 110 and the network 112, to a device in the network 112. For example, the network device to which the request is sent may be a server such as the server 118. The server 118 may comprise a computer program and/or a machine that waits for requests from other machines or software (clients) and responds to them. A server typically processes data. One purpose of a server is to share data and/or hardware and/or software resources among clients. This architecture is called the client-server model. The clients may run on the same computer or may connect to the server over a network. Examples of computing servers include database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. The term server may be construed broadly to include any computerized process that shares a resource to one or more client processes.

In response to the request, at block B204 the network device may connect the A/V recording and communication doorbell 100 to the user's client device 114 through the user's network 110 and the network 112. At block B206, the A/V recording and communication doorbell 100 may record available audio and/or video data using the camera 102, the microphone 104, and/or any other sensor available. At block B208, the audio and/or video data is transmitted (streamed) from the A/V recording and communication doorbell 100 to the user's client device 114 via the user's network 110 and the network 112. At block B210, the user may receive a notification on his or her client device 114 with a prompt to either accept or deny the call.

At block B212, the process determines whether the user has accepted or denied the call. If the user denies the notification, then the process advances to block B214, where the audio and/or video data is recorded and stored at a cloud server. The session then ends at block B216 and the connection between the A/V recording and communication doorbell 100 and the user's client device 114 is terminated. If, however, the user accepts the notification, then at block B218 the user communicates with the visitor through the user's client device 114 while audio and/or video data captured by the camera 102, the microphone 104, and/or other sensors is streamed to the user's client device 114. At the end of the call, the user may terminate the connection between the user's client device 114 and the A/V recording and communication doorbell 100 and the session ends at block B216. In some embodiments, the audio and/or video data may be recorded and stored at a cloud server (block B214) even if the user accepts the notification and communicates with the visitor through the user's client device 114.

Many of today's homes include a wired doorbell system that does not have A/V communication capabilities. Instead, standard wired doorbell systems include a button outside the home next to the front door. The button activates a signaling device (such as a bell or a buzzer) inside the building. Pressing the doorbell button momentarily closes the doorbell circuit, which may be, for example, a single-pole, single-throw (SPST) push button switch. One terminal of the button is wired to a terminal on a transformer. The transformer steps down the 120-volt or 240-volt household AC electrical power to a lower voltage, typically 16 to 24 volts. Another terminal on the transformer is wired to a terminal on the signaling device. Another terminal on the signaling device is wired to the other terminal on the button. A common signaling device includes two flat metal bar resonators, which are struck by plungers operated by two solenoids. The flat bars are tuned to different notes. When the doorbell button is pressed, the first solenoid's plunger strikes one of the bars, and when the button is released, a spring on the plunger pushes the plunger up, causing it to strike the other bar, creating a two-tone sound (“ding-dong”).

Many current A/V recording and communication doorbell systems (other than the present embodiments) are incompatible with existing wired doorbell systems of the type described in the preceding paragraph. One reason for this incompatibility is that the A/V recording and communication doorbell draws an amount of power from the household AC electrical power supply that is above the threshold necessary for causing the signaling device to sound. The A/V recording and communication doorbell thus causes frequent inadvertent sounding of the signaling device, which is not only bothersome to the home's occupant(s), but also undermines the usefulness of the doorbell. The present embodiments solve this problem by limiting the power consumption of the A/V recording and communication doorbell to an amount that is below the threshold necessary for causing the signaling device to sound. Embodiments of the present A/V recording and communication doorbell can thus be connected to the existing household AC power supply and the existing signaling device without causing inadvertent sounding of the signaling device.

Several advantages flow from the ability of the present embodiments to be connected to the existing household AC power supply. For example, the camera of the present A/V recording and communication doorbell can be powered on continuously. In a typical battery-powered A/V recording and communication doorbell, the camera is powered on only part of the time so that the battery does not drain too rapidly. The present embodiments, by contrast, do not rely on a battery as a primary (or sole) power supply, and are thus able to keep the camera powered on continuously. Because the camera is able to be powered on continuously, it can always be recording, and recorded footage can be continuously stored in a rolling buffer or sliding window. In some embodiments, about 10-15 seconds of recorded footage can be continuously stored in the rolling buffer or sliding window. Also because the camera is able to be powered on continuously, it can be used for motion detection, thus eliminating any need for a separate motion detection device, such as a passive infrared sensor (PIR). Eliminating the PIR simplifies the design of the A/V recording and communication doorbell and enables the doorbell to be made more compact. Also because the camera is able to be powered on continuously, it can be used as a light detector for use in controlling the current state of the IR cut filter and turning the IR LED on and off. Using the camera as a light detector eliminates any need for a separate light detector, thereby further simplifying the design of the A/V recording and communication doorbell and enabling the doorbell to be made even more compact.

FIGS. 3-13 illustrate one embodiment of a low-power-consumption A/V recording and communication doorbell 130 according to various aspects of the present disclosure. FIG. 3 is a functional block diagram illustrating various components of the A/V recording and communication doorbell 130 and their relationships to one another. For example, the A/V recording and communication doorbell 130 includes a pair of terminals 131, 132 configured to be connected to a source of external AC (alternating-current) power, such as a household AC power supply 134 (may also be referred to as AC mains). The AC power 134 may have a voltage in the range of 16-24 VAC, for example. The incoming AC power 134 may be converted to DC (direct-current) by an AC/DC rectifier 136. An output of the AC/DC rectifier 136 may be connected to an input of a DC/DC converter 138, which may step down the voltage from the output of the AC/DC rectifier 136 from 16-24 VDC to a lower voltage of about 5 VDC, for example. In various embodiments, the output of the DC/DC converter 138 may be in a range of from about 2.5 V to about 7.5 V, for example.

With further reference to FIG. 3, the output of the DC/DC converter 138 is connected to a power manager 140, which may comprise an integrated circuit including a processor core, memory, and/or programmable input/output peripherals. In one non-limiting example, the power manager 140 may be an off-the-shelf component, such as the BQ24773 chip manufactured by Texas Instruments. As described in detail below, the power manager 140 controls, among other things, an amount of power drawn from the external power supply 134, as well as an amount of supplemental power drawn from a battery 142, to power the A/V recording and communication doorbell 130. The power manager 140 may, for example, limit the amount of power drawn from the external power supply 134 so that a threshold power draw is not exceeded. In one non-limiting example, the threshold power, as measured at the output of the DC/DC converter 138, may be equal to 1.4 A. The power manager 140 may also control an amount of power drawn from the external power supply 134 and directed to the battery 142 for recharging of the battery 142. An output of the power manager 140 is connected to a power sequencer 144, which controls a sequence of power delivery to other components of the A/V recording and communication doorbell 130, including a communication module 146, a front button 148, a microphone 150, a speaker driver 151, a speaker 152, an audio CODEC (Coder-DECoder) 153, a camera 154, an infrared (IR) light source 156, an IR cut filter 158, a processor 160 (may also be referred to as a controller 160), a plurality of light indicators 162, and a controller 164 for the light indicators 162. Each of these components is described in detail below. The power sequencer 144 may comprise an integrated circuit including a processor core, memory, and/or programmable input/output peripherals. In one non-limiting example, the power sequencer 144 may be an off-the-shelf component, such as the RT5024 chip manufactured by Richtek.

With further reference to FIG. 3, the A/V recording and communication doorbell 130 further comprises an electronic switch 166 that closes when the front button 148 is depressed. When the electronic switch 166 closes, power from the AC power source 134 is diverted through a signaling device 168 that is external to the A/V recording and communication doorbell 130 to cause the signaling device 168 to emit a sound, as further described below. In one non-limiting example, the electronic switch 166 may be a triac device. The A/V recording and communication doorbell 130 further comprises a reset button 170 configured to initiate a hard reset of the processor 160, as further described below.

With further reference to FIG. 3, the processor 160 may perform data processing and various other functions, as described below. The processor 160 may comprise an integrated circuit including a processor core, memory 172, non-volatile memory 174, and/or programmable input/output peripherals (not shown). The memory 172 may comprise, for example, DDR3 (double data rate type three synchronous dynamic random-access memory). The non-volatile memory 174 may comprise, for example, NAND flash memory. In the embodiment illustrated in FIG. 3, the memory 172 and the non-volatile memory 174 are illustrated within the box representing the processor 160. It is to be understood that the embodiment illustrated in FIG. 3 is merely an example, and in some embodiments the memory 172 and/or the non-volatile memory 174 are not necessarily physically incorporated with the processor 160. The memory 172 and/or the non-volatile memory 174, regardless of their physical location, may be shared by one or more other components (in addition to the processor 160) of the present A/V recording and communication doorbell 130.

The transfer of digital audio between the user and a visitor may be compressed and decompressed using the audio CODEC 153, which is operatively coupled to the processor 160. When the visitor speaks, audio from the visitor is compressed by the audio CODEC 153, digital audio data is sent through the communication module 146 to the network 112 via the user's network 110, routed by the server 118 and delivered to the user's client device 114. When the user speaks, after being transferred through the network 112, the user's network 110, and the communication module 146, the digital audio data is decompressed by the audio CODEC 153 and emitted to the visitor through the speaker 152, which is driven by the speaker driver 151.

With further reference to FIG. 3, some of the present embodiments may include a shunt 176 connected in parallel with the signaling device 168. The shunt 176 facilitates the ability of the A/V recording and communication doorbell 130 to draw power from the AC power source 134 without inadvertently triggering the signaling device 168. The shunt 176, during normal standby operation, presents a relatively low electrical impedance, such as a few ohms, across the terminals of the signaling device 168. Most of the current drawn by the A/V recording and communication doorbell 130, therefore, flows through the shunt 176, and not through the signaling device 168. The shunt 176, however, contains electronic circuitry (described below) that switches the shunt 176 between a state of low impedance, such as a few ohms, for example, and a state of high impedance, such as >1K ohms, for example. When the front button 148 of the A/V recording and communication doorbell 130 is pressed, the electronic switch 166 closes, causing the voltage from the AC power source 134 to be impressed mostly across the shunt 176 and the signaling device 168 in parallel, while a small amount of voltage, such as about 1V, is impressed across the electronic switch 166. The circuitry in the shunt 176 senses this voltage, and switches the shunt 176 to the high impedance state, so that power from the AC power source 134 is diverted through the signaling device 168. The diverted AC power 134 is above the threshold necessary to cause the signaling device 168 to emit a sound. Pressing the front button 148 of the doorbell 130 therefore causes the signaling device 168 to “ring,” alerting any person(s) within the structure to which the doorbell 130 is mounted that there is a visitor at the front door (or at another location corresponding to the location of the doorbell 130). In one non-limiting example, the electronic switch 166 may be a triac device.

With reference to FIGS. 4-6, the A/V recording and communication doorbell 130 further comprises a housing 178 having an enclosure 180 (FIG. 6), a back plate 182 secured to the rear of the enclosure 180, and a shell 184 overlying the enclosure 180. With reference to FIG. 6, the shell 184 includes a recess 186 that is sized and shaped to receive the enclosure 180 in a close fitting engagement, such that outer surfaces of the enclosure 180 abut conforming inner surfaces of the shell 184. Exterior dimensions of the enclosure 180 may be closely matched with interior dimensions of the shell 184 such that friction maintains the shell 184 about the enclosure 180. Alternatively, or in addition, the enclosure 180 and/or the shell 184 may include mating features 188, such as one or more tabs, grooves, slots, posts, etc. to assist in maintaining the shell 184 about the enclosure 180. The back plate 182 is sized and shaped such that the edges of the back plate 182 extend outward from the edges of the enclosure 180, thereby creating a lip 190 against which the shell 184 abuts when the shell 184 is mated with the enclosure 180, as shown in FIGS. 4 and 5. In some embodiments, multiple shells 184 in different colors may be provided so that the end user may customize the appearance of his or her A/V recording and communication doorbell 130. For example, the A/V recording and communication doorbell 130 may be packaged and sold with multiple shells 184 in different colors in the same package.

With reference to FIG. 4, a front surface of the A/V recording and communication doorbell 130 includes the button 148 (may also be referred to as front button 148, FIG. 3), which is operatively connected to the processor 160. In a process similar to that described above with reference to FIG. 2, when a visitor presses the front button 148, an alert may be sent to the user's client device to notify the user that someone is at his or her front door (or at another location corresponding to the location of the A/V recording and communication doorbell 130). With further reference to FIG. 4, the A/V recording and communication doorbell 130 further includes the camera 154, which is operatively connected to the processor 160, and which is located behind a shield 192. As described in detail below, the camera 154 is configured to capture video images from within its field of view. Those video images can be streamed to the user's client device and/or uploaded to a remote network device for later viewing according to a process similar to that described above with reference to FIG. 2.

With reference to FIG. 5, a pair of terminal screws 194 extends through the back plate 182. The terminal screws 194 are connected at their inner ends to the terminals 131, 132 (FIG. 3) within the A/V recording and communication doorbell 130. The terminal screws 194 are configured to receive electrical wires to connect to the A/V recording and communication doorbell 130, through the terminals 131, 132, to the household AC power supply 134 of the structure on which the A/V recording and communication doorbell 130 is mounted. In the illustrated embodiment, the terminal screws 194 are located within a recessed portion 196 of the rear surface 198 of the back plate 182 so that the terminal screws 194 do not protrude from the outer envelope of the A/V recording and communication doorbell 130. The A/V recording and communication doorbell 130 can thus be mounted to a mounting surface with the rear surface 198 of the back plate 182 abutting the mounting surface. The back plate 182 includes apertures 200 adjacent its upper and lower edges to accommodate mounting hardware, such as screws (not shown), for securing the back plate 182 (and thus the A/V recording and communication doorbell 130) to the mounting surface. With reference to FIG. 6, the enclosure 180 includes corresponding apertures 202 adjacent its upper and lower edges that align with the apertures 200 in the back plate 182 to accommodate the mounting hardware. In certain embodiments, the A/V recording and communication doorbell 130 may include a mounting plate or bracket (not shown) to facilitate securing the A/V recording and communication doorbell 130 to the mounting surface.

With further reference to FIG. 6, the shell 184 includes a central opening 204 in a front surface. The central opening 204 is sized and shaped to accommodate the shield 192. In the illustrated embodiment, the shield 192 is substantially rectangular, and includes a central opening 206 through which the front button 148 protrudes. The shield 192 defines a plane parallel to and in front of a front surface 208 of the enclosure 180. When the shell 184 is mated with the enclosure 180, as shown in FIGS. 4 and 10, the shield 192 resides within the central opening 204 of the shell 184 such that a front surface 210 of the shield 192 is substantially flush with a front surface 212 of the shell 184 and there is little or no gap (FIG. 4) between the outer edges of the shield 192 and the inner edges of the central opening 204 in the shell 184.

With further reference to FIG. 6, the shield 192 includes an upper portion 214 (located above and to the sides of the front button 148) and a lower portion 216 (located below and to the sides of the front button 148). The upper and lower portions 214, 216 of the shield 192 may be separate pieces, and may comprise different materials. The upper portion 214 of the shield 192 may be transparent or translucent so that it does not interfere with the field of view of the camera 154. For example, in certain embodiments the upper portion 214 of the shield 192 may comprise glass or plastic. As described in detail below, the microphone 150, which is operatively connected to the processor 160, is located behind the upper portion 214 of the shield 192. The upper portion 214, therefore, may include an opening 218 that facilitates the passage of sound through the shield 192 so that the microphone 150 is better able to pick up sounds from the area around the A/V recording and communication doorbell 130.

The lower portion 216 of the shield 192 may comprise a material that is substantially transparent to infrared (IR) light, but partially or mostly opaque with respect to light in the visible spectrum. For example, in certain embodiments the lower portion 216 of the shield 192 may comprise a plastic, such as polycarbonate. The lower portion 216 of the shield 192, therefore, does not interfere with transmission of IR light from the IR light source 156, which is located behind the lower portion 216. As described in detail below, the IR light source 156 and the IR cut filter 158, which are both operatively connected to the processor 160, facilitate “night vision” functionality of the camera 154.

The upper portion 214 and/or the lower portion 216 of the shield 192 may abut an underlying cover 220 (FIG. 10), which may be integral with the enclosure 180 or may be a separate piece. The cover 220, which may be opaque, may include a first opening 222 corresponding to the location of the camera 154, a second opening (not shown) corresponding to the location of the microphone 150 and the opening 218 in the upper portion 214 of the shield 192, and a third opening (not shown) corresponding to the location of the IR light source 156.

FIGS. 7-10 illustrate various internal components of the A/V recording and communication doorbell 130. FIGS. 7-9 are front perspective views of the doorbell 130 with the shell 184 and the enclosure 180 removed, while FIG. 10 is a right-side cross-sectional view of the doorbell 130 taken through the line 10-10 in FIG. 4. With reference to FIGS. 7 and 8, the A/V recording and communication doorbell 130 further comprises a main printed circuit board (PCB) 224 and a front PCB 226. With reference to FIG. 8, the front PCB 226 comprises a button actuator 228. With reference to FIGS. 7, 8, and 10, the front button 148 is located in front of the button actuator 228. The front button 148 includes a stem 230 (FIG. 10) that extends into the housing 178 to contact the button actuator 228. When the front button 148 is pressed, the stem 230 depresses the button actuator 228, thereby closing the electronic switch 166 (FIG. 8), as described below.

With reference to FIG. 8, the front PCB 226 further comprises the light indicators 162, which may illuminate when the front button 148 of the doorbell 130 is pressed. In the illustrated embodiment, the light indicators 162 comprise light-emitting diodes (LEDs 162) that are surface mounted to the front surface of the front PCB 226 and are arranged in a circle around the button actuator 228. The present embodiments are not limited to the light indicators 162 being LEDs, and in alternative embodiments the light indicators 162 may comprise any other type of light-emitting device. The present embodiments are also not limited by the number of light indicators 162 shown in FIG. 8, nor by the pattern in which they are arranged.

With reference to FIG. 7, the doorbell 130 further comprises a light pipe 232. The light pipe 232 is a transparent or translucent ring that encircles the front button 148. With reference to FIG. 4, the light pipe 232 resides in an annular space between the front button 148 and the central opening 206 in the shield 192, with a front surface 234 of the light pipe 232 being substantially flush with the front surface 210 of the shield 192. With reference to FIGS. 7 and 10, a rear portion of light pipe 232 includes a plurality of posts 236 whose positions correspond to the positions of the LEDs 162. When the LEDs 162 are illuminated, light is transmitted through the posts 236 and the body of the light pipe 232 so that the light is visible at the front surface 234 of the light pipe 232. The LEDs 162 and the light pipe 232 thus provide a ring of illumination around the front button 148. The light pipe 232 may comprise a plastic, for example, or any other suitable material capable of transmitting light.

The LEDs 162 and the light pipe 232 may function as visual indicators for a visitor and/or a user. For example, the LEDs 162 may illuminate upon activation or stay illuminated continuously. In one aspect, the LEDs 162 may change color to indicate that the front button 148 has been pressed. The LEDs 162 may also indicate that the battery 142 needs recharging, or that the battery 142 is currently being charged, or that charging of the battery 142 has been completed. The LEDs 162 may indicate that a connection to the user's network is good, limited, poor, or not connected. The LEDs 162 may be used to guide the user through setup or installation steps using visual cues, potentially coupled with audio cues emitted from the speaker 152.

With further reference to FIG. 7, the A/V recording and communication doorbell 130 further comprises a rechargeable battery 142. As described in further detail below, the A/V recording and communication doorbell 130 is connected to an external power source 134 (FIG. 3), such as AC mains. The A/V recording and communication doorbell 130 is primarily powered by the external power source 134, but may also draw power from the rechargeable battery 142 so as not to exceed a threshold amount of power from the external power source 134, to thereby avoid inadvertently sounding the signaling device 168. With reference to FIG. 3, the battery 142 is operatively connected to the power manager 140. As described below, the power manager 140 controls an amount of power drawn from the battery 142 to supplement the power drawn from the external AC power source 134 to power the A/V recording and communication doorbell 130 when supplemental power is needed. The power manager 140 also controls recharging of the battery 142 using power drawn from the external power source 134. The battery 142 may comprise, for example, a lithium-ion battery, or any other type of rechargeable battery.

With further reference to FIG. 7, the A/V recording and communication doorbell 130 further comprises the camera 154. The camera 154 is coupled to a front surface of the front PCB 226, and includes a lens 238 and an imaging processor 240 (FIG. 9). The camera lens 238 may be a lens capable of focusing light into the camera 154 so that clear images may be captured. The camera 154 may comprise, for example, a high definition (HD) video camera, such as one capable of capturing video images at an image display resolution of 720p or better. In certain of the present embodiments, the camera 154 may be used to detect motion within its field of view, as described below.

With further reference to FIG. 7, the A/V recording and communication doorbell 130 further comprises an infrared (IR) light source 242. In the illustrated embodiment, the IR light source 242 comprises an IR light-emitting diode (LED) 242 coupled to an IR LED printed circuit board (PCB) 244. In alternative embodiments, the IR LED 242 may not comprise a separate PCB 244, and may, for example, be coupled to the front PCB 226.

With reference to FIGS. 7 and 10, the IR LED PCB 244 is located below the front button 148 (FIG. 7) and behind the lower portion 216 of the shield 192 (FIG. 10). As described above, the lower portion 216 of the shield 192 is transparent to IR light, but may be opaque with respect to light in the visible spectrum. FIG. 7A illustrates an alternative embodiment of the IR LED PCB 244′ comprising three IR LEDs 242. In an embodiment including the IR LED PCB 244′ of FIG. 7A, or including any IR LED PCB having more than one IR LED 242, the size of the third opening in the cover may be increased to accommodate the larger size of the IR LED PCB 244′.

The IR LED 242 may be triggered to activate when a low level of ambient light is detected. When activated, IR light emitted from the IR LED 242 illuminates the camera 154′s field of view. The camera 154, which may be configured to detect IR light, may then capture the IR light emitted by the IR LED 242 as it reflects off objects within the camera 154′s field of view, so that the A/V recording and communication doorbell 130 can clearly capture images at night (may be referred to as “night vision”).

With reference to FIG. 9, the A/V recording and communication doorbell 130 further comprises an IR cut filter 158. The IR cut filter 158 is a mechanical shutter that can be selectively positioned between the lens 238 and the image sensor of the camera 154. During daylight hours, or whenever there is a sufficient amount of ambient light, the IR cut filter 158 is positioned between the lens 238 and the image sensor to filter out IR light so that it does not distort the colors of images as the human eye sees them. During nighttime hours, or whenever there is little to no ambient light, the IR cut filter 158 is withdrawn from the space between the lens 238 and the image sensor, so that the camera 154 is sensitive to IR light (“night vision”). In some embodiments, the camera 154 acts as a light detector for use in controlling the current state of the IR cut filter 158 and turning the IR LED 242 on and off. Using the camera 154 as a light detector is facilitated in some embodiments by the fact that the A/V recording and communication doorbell 130 is powered by a connection to AC mains, and the camera 154, therefore, is always powered on. In other embodiments, however, the A/V recording and communication doorbell 130 may include a light sensor separate from the camera 154 for use in controlling the IR cut filter 158 and the IR LED 242.

With reference back to FIG. 6, the A/V recording and communication doorbell 130 further comprises a reset button 170. The reset button 170 contacts a reset button actuator 246 (FIG. 8) coupled to the front PCB 226. When the reset button 170 is pressed, it may contact the reset button actuator 246, which may trigger the erasing of any data stored at the non-volatile memory 174 and/or at the memory 172 (FIG. 3), and/or may trigger a reboot of the processor 160.

FIGS. 11-13 further illustrate internal components of the A/V recording and communication doorbell 130. FIGS. 11-13 are rear perspective views of the doorbell 130 with the back plate 182 and additional components removed. For example, in FIG. 11 the back plate 182 is removed, while in FIG. 12 the back plate 182 and the main PCB 224 are removed, and in FIG. 13 the back plate 182, the main PCB 224, and the front PCB 226 are removed. With reference to FIG. 11, several components are coupled to the rear surface of the main PCB 224, including the communication module 146, the processor 160, memory 172, and non-volatile memory 174. The functions of each of these components are described below. With reference to FIG. 12, several components are coupled to the rear surface of the front PCB 226, including the power manager 140, the power sequencer 144, the AC/DC rectifier 136, the DC/DC converter 138, and the controller 164 for the light indicators 162. The functions of each of these components are also described below. With reference to FIG. 13, several components are visible within the enclosure 180, including the microphone 150, a speaker chamber 248 (in which the speaker 152 is located), and an antenna 250 for the communication module 146. The functions of each of these components are also described below.

With reference to FIG. 7, the antenna 250 is coupled to the front surface of the main PCB 224 and operatively connected to the communication module 146, which is coupled to the rear surface of the main PCB 224 (FIG. 11). The microphone 150, which may also be coupled to the front surface of the main PCB 224, is located near the opening 218 (FIG. 4) in the upper portion 214 of the shield 192 so that sounds emanating from the area around the A/V recording and communication doorbell 130 can pass through the opening 218 and be detected by the microphone 150. With reference to FIG. 13, the speaker chamber 248 is located near the bottom of the enclosure 180. The speaker chamber 248 comprises a hollow enclosure in which the speaker 152 is located. The hollow speaker chamber 248 amplifies the sounds made by the speaker 152 so that they can be better heard by a visitor in the area near the A/V recording and communication doorbell 130. With reference to FIGS. 5 and 13, the lower surface 252 of the shell 184 and the lower surface (not shown) of the enclosure 180 may include an acoustical opening 254 through which the sounds made by the speaker 152 can pass so that they can be better heard by a visitor in the area near the A/V recording and communication doorbell 130. In the illustrated embodiment, the acoustical opening 254 is shaped generally as a rectangle having a length extending substantially across the lower surface 252 of the shell 184 (and also the enclosure 180). The illustrated shape is, however, just one example. With reference to FIG. 5, the lower surface 252 of the shell 184 may further include an opening 256 for receiving a security screw (not shown). The security screw may extend through the opening 256 and into a similarly located opening in the enclosure 180 to secure the shell 184 to the enclosure 180. If the doorbell 130 is mounted to a mounting bracket (not shown), the security screw may also maintain the doorbell 130 on the mounting bracket.

With reference to FIG. 13, the A/V recording and communication doorbell 130 may further include a battery heater 258. The present A/V recording and communication doorbell 130 is configured for outdoor use, including in cold climates. Cold temperatures, however, can cause negative performance issues for rechargeable batteries, such as reduced energy capacity, increased internal resistance, reduced ability to charge without damage, and reduced ability to supply load current. The battery heater 258 helps to keep the rechargeable battery 142 warm in order to reduce or eliminate the foregoing negative performance issues. In the illustrated embodiment, the battery heater 258 comprises a substantially flat, thin sheet abutting a side surface of the rechargeable battery 142. The battery heater 258 may comprise, for example, an electrically resistive heating element that produces heat when electrical current is passed through it. The battery heater 258 may thus be operatively coupled to the power manager 140 and/or the power sequencer 144 (FIG. 12). In some embodiments, the rechargeable battery 142 may include a thermally sensitive resistor (“thermistor,” not shown) operatively connected to the processor 160 so that the battery 142′s temperature can be monitored and the amount of power supplied to the battery heater 258 can be adaptively controlled to keep the rechargeable battery 142 within a desired temperature range.

FIG. 14 is a flowchart illustrating an embodiment of a process for drawing supplemental power from the battery 142 of the present A/V recording and communication doorbell 130 in order to avoid inadvertent sounding of the connected signaling device 168. At block B280, the A/V recording and communication doorbell 130 draws power, below a threshold power, from an external power source. The external power source may be, for example, the AC power source 134, as shown in FIG. 3. The threshold power may be, for example, the power level at which the signaling device 168 (FIG. 3) would sound. In one non-limiting example, the threshold power may be measured at the output of the DC/DC converter 138 (FIG. 3). The threshold power may be measured by the power manager 140 (FIG. 3), for example. In one non-limiting example, the threshold power, as measured at the output of the DC/DC converter 138, may be equal to 1.4 A.

At block B282, the process determines whether the power drawn from the external power source 134 has reached the threshold power. In some embodiments, the power manager 140 (FIG. 3), for example, may determine whether the power drawn from the external power source 134 has reached the threshold power. If the power drawn from the external power source 134 has not reached the threshold power, then the process loops back to block B280. If, however, the power drawn from the external power source 134 has reached the threshold power, then the process moves to block B284. At block B284, the A/V recording and communication doorbell 130 draws supplemental power from the battery 142 as needed so that the power drawn from the external power source 134 does not exceed the threshold power. In this manner, the process of FIG. 14 avoids inadvertent sounding of the connected signaling device 168. Examples of scenarios where the power drawn from the external power source 134 might reach the threshold power include, but are not limited to, when switching the IR cut filter 158 from daytime mode to nighttime mode (and vice versa), or when a call is in progress between a visitor at the A/V recording and communication doorbell 130 and a user using a client device and the IR light source 156 is illuminated. In some embodiments, when the power being drawn from the external power source 134 is below the threshold power, the power manager 140 may direct a portion of the power drawn from the external power source 134 to the battery 142 in order to recharge the battery 142.

As discussed above, and with reference back to FIG. 3, some of the present embodiments may include a shunt 176 connected in parallel across the terminals of the signaling device 168. The shunt 176 facilitates the ability of the A/V recording and communication doorbell 130 to draw power from the AC power source 134 without inadvertently triggering the signaling device 168. FIG. 15 illustrates an example embodiment of the shunt 176. With reference to FIG. 15, the shunt 176 comprises a full-wave bridge rectifier 300, a capacitor 302, a diode 304, a shunt switch 306, a first resistor R_(Shunt) 308, and a second resistor R_(Bias) 310. In some embodiments, the shunt switch 306 may be an opto-coupled switch, for example. The first resistor R_(Shunt) 308 presents a relatively low electrical impedance, such as a few ohms for example, while the second resistor R_(Bias) 310 presents a higher electrical impedance, such as >1K ohms for example.

During normal standby operation, the shunt switch 306 is dosed. The shunt 176, therefore, presents a relatively low electrical impedance across the terminals AC₁, AC₂ of the signaling device 168, because the impedance of the first resistor R_(Shunt) 308 is relatively low and the impedance of the switch is even lower, such as about 1 ohm or less in one example. Most of the current drawn by the A/V recording and communication doorbell 130, therefore, flows through the shunt 176, and not through the signaling device 168. When the front button 148 of the A/V recording and communication doorbell 130 is pressed, however, the electronic switch 166 closes, causing the voltage from the AC power source 134 to be impressed mostly across the shunt 176 and the signaling device 168 in parallel, while a small amount of voltage, such as about 1V in one example, is impressed across the electronic switch 166, if it is implemented as a. triac for example. The circuitry in the shunt 176 senses the voltage across its terminals AC₁, AC₂, causing the shunt switch 306 to open, which puts the shunt 176 into a high impedance state. When the shunt 176 receives enough AC voltage, the full-wave bridge rectifier 300 provides and outputs enough DC voltage such that the diode 304 biased by resistor 310 R_(bias) conducts enough current to cause the switch 306 to change to an open or very high impedance state. Thus, the switching action of the shunt 176 makes nearly all available power from the AC power source 134 usable by the signaling device 168, when it is desired. The amount of diverted AC power from the AC power source 134 is above the threshold necessary to cause the signaling device 168 to emit a sound. Pressing the front button 148 of the doorbell 130 therefore causes the signaling device 168 to sound, alerting any person(s) within the structure to which the doorbell 130 is mounted that there is a visitor at the front door (or at another location corresponding to the location of the doorbell 130).

With continued reference to FIG. 15, the shunt 176 further comprises a first comparator circuit 312 and a second comparator circuit 314. FIGS. 16 and 17 are circuit diagrams illustrating example embodiments of the first and second comparator 324 circuits 312, 314, respectively, of the shunt 176 of FIG. 15. The comparators 312, 314 of FIGS. 16 and 17 are both open collector-type or open drain-type. These types of comparators are advantageous because they allow the outputs to be tied together without conflict, commonly known as a “wired-OR” connection. As further described below, the first comparator circuit 312 serves the purpose of returning the state of the shunt switch 306 to the normally closed, low impedance state, when an opening event is detected at the electronic switch 166 (FIG. 3). The second comparator circuit 314 serves as a time out safety trigger, returning the state of the shunt switch 306 to the normally closed, low impedance state, in the event that the first comparator circuit 312 fails to perform its intended function.

With reference to FIG. 16, the first comparator circuit 312 comprises a first comparator 316, and an RC network at each of its two inputs 318, 320. The first (positive) input 318 of the first comparator 316 has an RC network having time constant Taui, where Tau₁=C₁*R₁. The second (negative) input 320 of the first comparator 316 has a voltage divider R₂/(R₂+R₃) and time constant Tau₂, where Tau₂=C₂*((R₂*R₃)/((R₂+R₃))). With reference to FIGS. 18 and 19, which are waveform diagrams for the first comparator circuit 312 of FIG. 16, the first comparator circuit 312 behavior is as follows. At time t₁, when the VDC at the capacitor 302 (FIG. 15) ramps up due to closure of the electronic switch (FIG. 3), both inputs 318, 320 to the first comparator 316 rise, with V₂ rising slower and asymptotically approaching V_(MAX)*(R₂/(R₂+R₃)), while V₁ rises faster and approaches V_(MAX). The ratio R₂/(R₂+R₃) may be chosen based on noise level consideration, particularly to ensure a positive drive with margin into the first comparator 316, for all times when the electronic switch 166 is closed. This assures the output V_(OUT) 322 of the first comparator 316 will be high impedance, since it is an open collector-type or an open drain-type output. Upon the electronic switch 166 opening at time t₂, the voltage V_(DC) at the capacitor 302 drops, and the voltage V₁ drops below V₂. The first comparator 316 responds by driving its output V_(OUT) 322 on, which pulls down the voltage and starts to turn off the diode 304 in the shunt switch 306. The shunt switch 306 responds by reverting back to its normally closed position.

With reference to FIG. 17, the second comparator circuit 314 comprises a second comparator 324, and an RC network at each of its two inputs 326, 328, but with the addition of a diode 330 in one of the series branches. The first (positive) input 326 of the second comparator 324 receives an attenuated version of VDC. More precisely, it receives a voltage given by V_(DC)*(R₆/(R₆+R₅)). In some embodiments, a capacitor (not shown) may be provided across R₆, as some filtering may be advantageous. The second (negative) input 328 of the second comparator 324 receives a voltage V₄ that rises slowly after V_(DC) ramps up. With reference to FIGS. 20 and 21, which are waveform diagrams for the second comparator circuit 314 of FIG. 17, the second comparator circuit 314 behavior is as follows. The rising waveform is given by V₄(t)=V_(DCMAX)*(1−exp(−t/Tau₃)) where Tau₃=C₄*R₄. While V₄ asymptotically approaches V_(DCMAX), it will hit V_(DCMAX)*(R₆/(R₆+R₅)) at time t₃, which is given by t₃=Tau₃*ln(1+R₆/R₅). Because of delays in the feedback mechanism, the voltage V₄ will actually go higher than V₃, causing the output V_(OUT) 332 of the second comparator 324 to be pulled low. This causes the diode 304 in the shunt switch 306 to discharge and turn off, which in turn causes the shunt switch 306 in SW₁ to revert to its normally closed position. The feedback mechanism is positive in that the turning off of the diode 304 puts the shunt 176 in a low impedance state, which causes the diode 304 to turn off even faster, since a low impedance state of the shunt 176 will collapse the AC₁, AC₂ terminals, if the electronic switch 166 is not closed. Reducing the voltage across AC₁, AC₂ will reduce the output of the full-wave bridge rectifier 300, V_(DC).

FIG. 22 is a flowchart illustrating an embodiment of a process for sounding the signaling device 168 connected to the present A/V recording and communication doorbell 130 according to various aspects of the present disclosure. At block B380, the A/V recording and communication doorbell 130 draws power from an external power source. The external power source may be, for example, the AC power source 134, as shown in FIG. 3. At block B382, the power flows through the signaling device 168 and the shunt 176 in parallel, and the shunt 176 is in the low impedance state. At block B384, the process determines whether the front button 148 has been depressed. If the front button 148 has not been depressed, then the process returns to block B382. If, however, the front button 148 has been depressed, then the process moves to block B386. At block B386, the electronic switch 166 closes, thereby causing the shunt 176 to transition to the high impedance state, which in turn causes the power drawn from the external power source to be diverted through the signaling device 168, which in turn causes the signaling device 168 to emit a sound. Also, when the front button 148 is depressed, the speaker 152 of the A/V recording and communication doorbell 130 may emit a sound to alert any persons within earshot of the speaker 152 that a visitor has pressed the front button 148.

FIG. 23 is a flowchart illustrating another embodiment of a process for sounding the signaling device 168 connected to the present A/V recording and communication doorbell 130 according to various aspects of the present disclosure. At block B350, the A/V recording and communication doorbell 130 draws power from an external power source. The external power source may be, for example, the AC power source 134, as shown in FIG. 3. At block B352, the power flows through the signaling device 168 and the shunt 176 in parallel, and the shunt 176 is in the low impedance state. At block B354, the process determines whether the front button 148 has been depressed. If the front button 148 has not been depressed, then the process returns to block B352. If, however, the front button 148 has been depressed, then the process moves to block B356. Also, when the front button 148 is depressed, the speaker 152 of the A/V recording and communication doorbell 130 may emit a sound to alert any persons within earshot of the speaker 152 that a visitor has pressed the front button 148.

At block B356, the process determines whether the power in the battery 142 is above a threshold. This determination helps ensure that the battery 142 does not drain completely while the power manager 140 is drawing supplemental power from the battery 142. If the power in the battery 142 is not above the threshold, then the process returns to block B352. If, however, the power in the battery 142 is above the threshold, then the process moves to block B358. At block B358, the electronic switch 166 closes, thereby causing the shunt 176 to transition to the high impedance state, which in turn causes the power drawn from the external power source to be diverted through the signaling device 168, which in turn causes the signaling device 168 to emit a sound.

Also at block B358, a first timer is activated. The first timer, which may be implemented by the processor 160, for example, enables several advantages. For example, the first timer enhances the compatibility of the present A/V recording and communication doorbell 130 with different types of existing signaling devices 168. Many existing signaling devices are of two types: electro-mechanical and electronic. Electro-mechanical signaling devices typically include a pair of metal tubes (or plates) that are tuned to different notes and act as resonators when struck. A plunger strikes the tubes or plates in quick succession, creating the “ding-dong” sound that is characteristic of many traditional doorbells. Electronic signaling devices, by contrast, typically include an audio speaker that acts as an electro-acoustic transducer. The speaker can in many instances be made to play custom ringtones having different durations.

During initial setup of some embodiments of the present A/V recording and communication doorbell 130, the duration of the first timer may be set according to the type of signaling device 168 with which it is paired, and the duration of the first timer may be customizable. For example, if the doorbell 130 is paired with an electro-mechanical signaling device 168, then the first timer may be set to a relatively short duration, such as 250 ms. A short duration for the first timer enables the electro-mechanical signaling device 168 to emit the characteristic “ding-dong” sound, because the plunger of the signaling device 168 will strike a first one of the metal tubes (or plates) when the electronic switch 166 closes and strike the second one of the metal tubes (or plates) when the electronic switch 166 opens. If the doorbell 130 is paired with an electro-mechanical signaling device 168, the duration of the first timer may be preset (not customizable by the user). If, however, the doorbell 130 is paired with an electronic signaling device 168, then the first timer may be set to a relatively long duration, such as from 1 second to 10 seconds, and the duration of the first timer may be selectable by the user. For example, if the user's electronic signaling device 168 plays a ringtone having a duration of about 3 seconds, then the user may set the duration of the first timer to be about 3 seconds.

During initial setup of some embodiments of the present A/V recording and communication doorbell 130, the user may be prompted to indicate what type of signaling device 168 the doorbell 130 is to be paired with. If the user indicates that the signaling device 168 is electro-mechanical, then the process may automatically set the duration of the first timer to a relatively short duration. If, however, the user indicates that the signaling device 168 is electronic, then the process may prompt the user to enter a desired duration for the first timer. In some embodiments, the process may prompt the user that the duration must be within a preset range.

At block B360, the process determines whether the first timer has expired. If the first timer has expired, then the process moves to block B364, which is described below. If, however, the first timer has not expired, then the process moves to block B362. At block B362, the process determines whether a notification has been received that a call to the user's client device has been answered. If no notification has been received that a call to the user's client device has been answered, then the process returns to block B360. If, however, a notification has been received that a call to the user's client device has been answered, then the process moves to block B364. At block B364, the electronic switch 166 opens, and a second timer is activated. The second timer, which may be implemented by the processor 160, for example, prevents a subsequent press of the front button 148 from closing the electronic switch 166, thereby preventing the visitor from repeatedly sounding the signaling device 168 (by rapidly pressing and re-pressing the front button 148). The second timer also allows time for the battery 142 to recharge. The process then moves to block B366. At block B366, the process determines whether the front button 148 has been depressed. If the front button 148 has not been depressed, then the process returns to block B366. If, however, the front button 148 has been depressed, then the process moves to block B368. At block B368, the process determines whether the second timer has expired. If the second timer has not expired, then the process returns to block B366. If, however, the second timer has expired, then the process returns to block B356.

In some embodiments, the present A/V recording and communication doorbell 130 may detect a visitor (by detecting motion) before the visitor presses the front button 148. In such cases, the A/V recording and communication doorbell 130 may initiate a call to the user's client device in a manner similar to that described above with respect to blocks B202-B210 of FIG. 2. If the user answers the call on his or her client device before the visitor presses the front button 148 of the A/V recording and communication doorbell 130, then the front button 148 may be blocked out as long as the call between the visitor and the user is still in progress. That is, if the visitor presses the front button 148 while the call between the visitor and the user is in progress, the electronic switch 166 may be prevented from closing. If, however, the visitor presses the front button 148 of the A/V recording and communication doorbell 130 before the user answers the call on his or her client device, then the process may proceed according to that described above with respect to FIG. 23 (beginning at block B354).

Some of the present embodiments provide advantageous motion detection algorithms and techniques. For example, during an initial setup process, or at any time after the A/V recording and communication doorbell 130 has been setup, the user may designate one or more zones within the field of view 400 of the camera 154 as motion zones of interest, also referred to as “intrusion zones.” With reference to FIG. 24, when configuring the camera 154′s motion detection, a configuration process may present the user with a visual representation of the field of view 400 of the camera 154. For example, an application executing on the user's client device 800, such as a smartphone, may show a live view from the camera 154 of the user's A/V recording and communication doorbell 130 on the display 806 of the user's client device 800 (FIG. 25). The configuration process may prompt the user to designate one or more intrusion zones 402 by selecting areas on the display 806 of the user's client device 800. For example, the user may draw one or more polygons 404, 406, 408 on the display 806 to designate the intrusion zone(s) 402. If the display 806 of the user's client device 800 is a touchscreen, the user may designate the intrusion zone(s) 402 by tracing the polygon(s) 404, 406, 408 on the display 806 with his or her finger. The configuration process may enable the user to designate intrusion zone(s) 402 having any shape and/or number of sides. For example, the intrusion zone(s) 402 may be regular polygons such as the square 404, rectangle 406, and hexagon 408 shown in FIG. 24, or any other type of regular polygon such as circles, pentagons, octagons, decagons, etc., or any type of irregular polygons. The configuration process may allow the user to designate any number of intrusion zones 402, such as one intrusion zone 402, two intrusion zones 402, three intrusion zones 402, etc. When all desired intrusion zones 402 have been created, the configuration process may prompt the user to save the intrusion zones 402, after which the created intrusion zones 402 may be sent from the user's client device 800 to a device in the network, such as a server 900C (FIG. 26), and to the user's A/V recording and communication doorbell 130 via the user's network 110 (FIG. 1).

After one or more intrusion zones 402 have been designated, embodiments of the present motion detection algorithms and techniques may incorporate those intrusion zones 402. For example, the camera 154, which may be powered on at all times, may continuously monitor motion within the field of view 400. The A/V recording and communication doorbell 130, however, may not begin recording and/or streaming video to the user's client device 800 unless and until a moving object enters one of the intrusion zones 402. The recording and/or streaming may continue until the moving object exits the intrusion zone 402 it earlier entered. Further, if the moving object stops moving, but remains in the intrusion zone 402, the recording and/or streaming may continue while the object remains stationary within the intrusion zone 402. This aspect of the present embodiments creates an advantage over systems that rely on other types of motion sensors, such as passive IR sensors, that typically only detect moving objects, and therefore do not typically record and/or stream stationary objects. The object may, of course, be a person.

Some of the present embodiments may incorporate motion detection algorithms and techniques that vary according to the level of ambient light. Generally, the quality of video recorded during daylight hours is good enough to detect moving objects of interest while correctly filtering out other unnecessary and unwanted moving objects (e.g. tree branches or flags swaying in the wind, sun glare, etc.). At night, however, the A/V recording and communication doorbell 130 turns on the IR light source 156 to increase the incoming light intensity. However, the light intensity level can be affected by other light sources, such as porchlights, outdoor security lights, streetlights, and headlights of passing cars. These light sources are preferably filtered out in order to reduce false positives (also referred to as false alarms). Thus, to accurately detect moving objects of interest while correctly filtering out other unnecessary and unwanted moving objects, embodiments of the present A/V recording and communication doorbell 130 may use different motion detection algorithms during the day versus at night.

For example, as discussed above, the A/V recording and communication doorbell 130 may not begin recording and/or streaming video to the user's client device 800 unless and until a moving object enters one of the intrusion zones 402. During periods of low levels of ambient light, however, such as after nightfall, the A/V recording and communication doorbell 130 may not begin recording and/or streaming video to the user's client device 800 unless and until the moving object that enters one of the intrusion zones 402 is a human. In some of the present embodiments, a process for determining whether a moving object is a human compares characteristics of the motion of the moving object with a dataset. For example, in each frame, the A/V recording and communication doorbell 130 may detect object regions, extract features from those object regions, and then compare those features with trained features in the dataset. If a comparison score and a confidence level are above a pre-defined threshold, then the algorithm returns a positive output (e.g. human) on the detected object region. Thus, for example, during daylight hours the A/V recording and communication doorbell 130 may begin recording and/or streaming video to the user's client device 800 as soon as any moving object enters one of the intrusion zones 402, but during nighttime hours the A/V recording and communication doorbell 130 may begin recording and/or streaming video to the user's client device 800 only if the moving object that entered one of the intrusion zones 402 is a human.

Differentiating between moving humans and moving non-human objects during nighttime hours may help to reduce false positives, because nighttime motion detection can be affected by uneven lighting conditions. For example, at night an A/V recording and communication doorbell may interpret a sudden change in ambient light, such as a porchlight being turned on, as motion. These kinds of false positives are reduced in the present embodiments by limiting recording and/or streaming video to the user's client device 800 to those instances when a detected object in an intrusion zone 402 is a human.

One example embodiment of a technique for determining whether a detected object in an intrusion zone 402 is a human is tracking moving objects by tracking the center of mass of each object, and predicting the trajectory of the object based on the observed motion of the center of mass. In some embodiments, the center of mass for an arbitrary shape of a detected region may be calculated as an average of multiple small centroid regions. With a finite number of small centroids, the total centroid can be calculated as:

The centroid of a finite set of k points x1, x2, . . . xk, in Rn is

C=(x ₁ +x ₂ + . . . +x _(k))/k

Tracking moving objects by tracking the center of mass of each object, and predicting the trajectory of the object based on the observed motion of the center of mass, can advantageously reduce false positives. For example, a person moving through the camera 154′s field of view 400 typically follows a predictable trajectory. If the person is moving in a first direction at a given instant, the person is likely to be moving in that same direction in the next instant. By contrast, many objects that move within the camera 154's field of view 400 follow very unpredictable trajectories. For example, a tree branch swaying in the breeze follows a somewhat random trajectory that depends upon which way the wind is blowing at any given moment. Thus, by attempting to predict the trajectory of the center of mass of an object moving through the camera 154's field of view 400, and then determining whether the object actually follows the predicted trajectory, the present embodiments can make an educated guess as to whether an object being tracked is an object of interest, such as a person, or another object, such as a tree branch. With this trajectory analysis, embodiments of the present A/V recording and communication doorbell 130 can successfully distinguish objects of interest from false positives by combining the trajectory analysis with detection of other changes in each frame.

Some of the present embodiments provide advantageous night vision algorithms and techniques for determining when to activate night vision mode and when to deactivate night vision mode. When night vision mode is activated, the IR light source 156 may be illuminated (turned on), the IR cut filter 158 may be turned off, and the camera 154 may transition from color mode to grayscale mode. Conversely, when night vision mode is deactivated, the IR light source 156 may be turned off, the IR cut filter 158 may be turned on, and the camera 154 may transition from grayscale mode to color mode.

In one example technique, some embodiments of the present night vision algorithms may measure the average luminance of the pixels and the average standard deviation of the pixels in each frame of video shot by the camera 154. The average luminance and the average standard deviation may then be tracked across frames by keeping a running average of each value. If the running averages of both values fall below a first pair of threshold values, then the A/V recording and communication doorbell 130 may activate night vision mode. Conversely, if the running averages of both values rise above a second pair of threshold values, then the A/V recording and communication doorbell 130 may deactivate night vision mode. For example, if the running average of the average luminance (AL) falls below a first threshold value (AL1), and the running average of the average standard deviation (ASD) falls below a first threshold value (ASD1), then the A/V recording and communication doorbell 130 may activate night vision mode. Conversely, if the running average of the average luminance (AL) rises above a second threshold value (AL2), and the running average of the average standard deviation (ASD) rises above a second threshold value (ASD2), then the A/V recording and communication doorbell 130 may deactivate night vision mode. Using separate threshold values for activating night vision mode versus deactivating night vision mode helps to prevent the A/V recording and communication doorbell 130 from oscillating between night vision mode and non-night vision mode during periods of fading light, such as dusk, and periods of rising light, such as dawn.

In some embodiments, sudden changes in light conditions may be ignored when tracking the running averages of the average luminance (AL) and the average standard deviation (ASD). For example, when night vision mode is active (e.g. after nightfall), if a porchlight is turned on near the A/V recording and communication doorbell 130 the average luminance and the average standard deviation in the pixels will suddenly spike. But, it is still after nightfall and the porchlight may soon be turned off, so it may be advantageous to keep night vision mode active. Some of the present embodiments, therefore, may not factor these sudden changes in the values AL and ASD into the running averages for those values.

In some embodiments, the proximity of the A/V recording and communication doorbell 130 to large objects or structures may affect whether night vision mode is activated or deactivated. For example, if the A/V recording and communication doorbell 130 is located directly across from a wall of a structure, a large percentage of the IR light generated by the IR light source 156 may be reflected back toward the camera 154. This reflected IR light could cause the A/V recording and communication doorbell 130 to deactivate night vision mode even under conditions of low ambient light, because the IR light reflected into the camera 154 increases the average light intensity value. A conventional night vision algorithm based on frame intensity level would cause night vision mode to be deactivates even when the current ambient light level was low. Thus, some of the present embodiments may compensate for this situation by measuring how many pixels in the field of view 400 of the camera 154 are saturated. Then, by comparing the number of saturated pixels to a threshold value, the process can determine whether to maintain the A/V recording and communication doorbell 130 in night vision mode. For example, if night vision mode is active, and the number of saturated pixels is above the threshold value, then night vision mode may remain active even when the values of AL and ASD rise above the second pair of threshold values (AL2, ASD2).

As described above, the present embodiments advantageously limit the power consumption of the A/V recording and communication doorbell to an amount that is below the threshold necessary for causing the signaling device to sound (except when the front button of the doorbell is pressed). The present A/V recording and communication doorbell can thus be connected to the existing household AC power supply and the existing signaling device without causing inadvertent sounding of the signaling device.

Several advantages flow from the ability of the present embodiments to be connected to the existing household AC power supply. For example, the camera of the present A/V recording and communication doorbell can be powered on continuously. In a typical battery-powered A/V recording and communication doorbell, the camera is powered on only part of the time so that the battery does not drain too rapidly. The present embodiments, by contrast, do not rely on a battery as a primary (or sole) power supply, and are thus able to keep the camera powered on continuously. Because the camera is able to be powered on continuously, it can always be recording, and recorded footage can be continuously stored in a rolling buffer or sliding window. In some embodiments, about 10-15 seconds of recorded footage can be continuously stored in the rolling buffer or sliding window. Also because the camera is able to be powered on continuously, it can be used for motion detection, thus eliminating any need for a separate motion detection device, such as a passive infrared sensor (PIR). Eliminating the PIR simplifies the design of the A/V recording and communication doorbell and enables the doorbell to be made more compact. Also because the camera is able to be powered on continuously, it can be used as a light detector for use in controlling the current state of the IR cut filter and turning the IR LED on and off. Using the camera as a light detector eliminates any need for a separate light detector, thereby further simplifying the design of the A/V recording and communication doorbell and enabling the doorbell to be made even more compact.

FIG. 25 is a functional block diagram of a client device 800 on which the present embodiments may be implemented according to various aspects of the present disclosure. The user's client device 114 described with reference to FIG. 1 may include some or all of the components and/or functionality of the client device 800. The client device 800 may comprise, for example, a smartphone.

With reference to FIG. 25, the client device 800 includes a processor 802, a memory 804, a user interface 806, a communication module 808, and a dataport 810. These components are communicatively coupled together by an interconnect bus 812. The processor 802 may include any processor used in smartphones and/or portable computing devices, such as an ARM processor (a processor based on the RISC (reduced instruction set computer) architecture developed by Advanced RISC Machines (ARM).). In some embodiments, the processor 802 may include one or more other processors, such as one or more conventional microprocessors, and/or one or more supplementary co-processors, such as math co-processors.

The memory 804 may include both operating memory, such as random access memory (RAM), as well as data storage, such as read-only memory (ROM), hard drives, flash memory, or any other suitable memory/storage element. The memory 804 may include removable memory elements, such as a CompactFlash card, a MultiMediaCard (MMC), and/or a Secure Digital (SD) card. In some embodiments, the memory 804 may comprise a combination of magnetic, optical, and/or semiconductor memory, and may include, for example, RAM, ROM, flash drive, and/or a hard disk or drive. The processor 802 and the memory 804 each may be, for example, located entirely within a single device, or may be connected to each other by a communication medium, such as a USB port, a serial port cable, a coaxial cable, an Ethernet-type cable, a telephone line, a radio frequency transceiver, or other similar wireless or wired medium or combination of the foregoing. For example, the processor 802 may be connected to the memory 804 via the dataport 810.

The user interface 806 may include any user interface or presentation elements suitable for a smartphone and/or a portable computing device, such as a keypad, a display screen, a touchscreen, a microphone, and a speaker. The communication module 808 is configured to handle communication links between the client device 800 and other, external devices or receivers, and to route incoming/outgoing data appropriately. For example, inbound data from the dataport 810 may be routed through the communication module 808 before being directed to the processor 802, and outbound data from the processor 802 may be routed through the communication module 808 before being directed to the dataport 810. The communication module 808 may include one or more transceiver modules capable of transmitting and receiving data, and using, for example, one or more protocols and/or technologies, such as GSM, UMTS (3GSM), IS-95 (CDMA one), IS-2000 (CDMA 2000), LTE, FDMA, TDMA, W-CDMA, CDMA, OFDMA, Wi-Fi, WiMAX, or any other protocol and/or technology.

The dataport 810 may be any type of connector used for physically interfacing with a smartphone and/or a portable computing device, such as a mini-USB port or an IPHONE®/IPOD® 30-pin connector or LIGHTNING® connector. In other embodiments, the dataport 810 may include multiple communication channels for simultaneous communication with, for example, other processors, servers, and/or client terminals.

The memory 804 may store instructions for communicating with other systems, such as a computer. The memory 804 may store, for example, a program (e.g., computer program code) adapted to direct the processor 802 in accordance with the present embodiments. The instructions also may include program elements, such as an operating system. While execution of sequences of instructions in the program causes the processor 802 to perform the process steps described herein, hard-wired circuitry may be used in place of, or in combination with, software/firmware instructions for implementation of the processes of the present embodiments. Thus, the present embodiments are not limited to any specific combination of hardware and software.

FIG. 26 is a functional block diagram of a general-purpose computing system on which the present embodiments may be implemented according to various aspects of present disclosure. The computer system 900 may execute at least some of the operations described above. The computer system 900 may be embodied in at least one of a personal computer (also referred to as a desktop computer) 900A, a portable computer (also referred to as a laptop or notebook computer) 900B, and/or a server 900C. A server is a computer program and/or a machine that waits for requests from other machines or software (clients) and responds to them. A server typically processes data. The purpose of a server is to share data and/or hardware and/or software resources among clients. This architecture is called the client—server model. The clients may run on the same computer or may connect to the server over a network. Examples of computing servers include database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. The term server may be construed broadly to include any computerized process that shares a resource to one or more client processes.

The computer system 900 may include at least one processor 910, memory 920, at least one storage device 930, and input/output (I/O) devices 940. Some or all of the components 910, 920, 930, 940 may be interconnected via a system bus 950. The processor 910 may be single- or multi-threaded and may have one or more cores. The processor 910 may execute instructions, such as those stored in the memory 920 and/or in the storage device 930. Information may be received and output using one or more I/O devices 940.

The memory 920 may store information, and may be a computer-readable medium, such as volatile or non-volatile memory. The storage device(s) 930 may provide storage for the system 900, and may be a computer-readable medium. In various aspects, the storage device(s) 930 may be a flash memory device, a hard disk device, an optical disk device, a tape device, or any other type of storage device.

The I/O devices 940 may provide input/output operations for the system 900. The I/O devices 940 may include a keyboard, a pointing device, and/or a microphone. The I/O devices 940 may further include a display unit for displaying graphical user interfaces, a speaker, and/or a printer. External data may be stored in one or more accessible external databases 960.

The features of the present embodiments described herein may be implemented in digital electronic circuitry, and/or in computer hardware, firmware, software, and/or in combinations thereof. Features of the present embodiments may be implemented in a computer program product tangibly embodied in an information carrier, such as a machine-readable storage device, and/or in a propagated signal, for execution by a programmable processor. Embodiments of the present method steps may be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output.

The features of the present embodiments described herein may be implemented in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and/or instructions from, and to transmit data and/or instructions to, a data storage system, at least one input device, and at least one output device. A computer program may include a set of instructions that may be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program may be written in any form of programming language, including compiled or interpreted languages, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

Suitable processors for the execution of a program of instructions may include, for example, both general and special purpose processors, and/or the sole processor or one of multiple processors of any kind of computer. Generally, a processor may receive instructions and/or data from a read only memory (ROM), or a random access memory (RAM), or both. Such a computer may include a processor for executing instructions and one or more memories for storing instructions and/or data.

Generally, a computer may also include, or be operatively coupled to communicate with, one or more mass storage devices for storing data files. Such devices include magnetic disks, such as internal hard disks and/or removable disks, magneto-optical disks, and/or optical disks. Storage devices suitable for tangibly embodying computer program instructions and/or data may include all forms of non-volatile memory, including for example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, one or more ASICs (application-specific integrated circuits).

To provide for interaction with a user, the features of the present embodiments may be implemented on a computer having a display device, such as an LCD (liquid crystal display) monitor, for displaying information to the user. The computer may further include a keyboard, a pointing device, such as a mouse or a trackball, and/or a touchscreen by which the user may provide input to the computer.

The features of the present embodiments may be implemented in a computer system that includes a back-end component, such as a data server, and/or that includes a middleware component, such as an application server or an Internet server, and/or that includes a front-end component, such as a client computer having a graphical user interface (GUI) and/or an Internet browser, or any combination of these. The components of the system may be connected by any form or medium of digital data communication, such as a communication network. Examples of communication networks may include, for example, a LAN (local area network), a WAN (wide area network), and/or the computers and networks forming the Internet.

The computer system may include clients and servers. A client and server may be remote from each other and interact through a network, such as those described herein. The relationship of client and server may arise by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

In a first aspect, a method for an audio/video (A/V) recording and communication doorbell system is provided, the A/V recording and communication doorbell including a camera, a speaker, a microphone, a power manager, a battery, an AC/DC rectifier, and a DC/DC converter, wherein the A/V recording and communication doorbell is connected to an external AC power source through the AC/DC rectifier and the DC/DC converter, the method comprising the power manager drawing power, up to a threshold power, from the AC power source, wherein the threshold power is measured at an output of the DC/DC converter; and when the power drawn from the AC power source reaches the threshold power, the power manager drawing supplemental power from the battery such that the power drawn from the AC power source never exceeds the threshold power as measured at the output of the DC/DC converter.

In an embodiment of the first aspect, the threshold power as measured at the output of the DC/DC converter is about 1.4 A.

In another embodiment of the first aspect, the A/V recording and communication doorbell further includes a button and an electronic switch, wherein when the button is depressed the electronic switch closes, thereby diverting power from the AC power source away from the power manager.

In another embodiment of the first aspect, when the electronic switch closes power from the AC power source is diverted through a signaling device to cause the signaling device to emit a sound.

In another embodiment of the first aspect, prior to the electronic switch closing, the power drawn from the AC power source flows through the signaling device and a shunt connected in parallel with the signaling device.

In another embodiment of the first aspect, prior to the electronic switch closing the shunt is in a low impedance state.

In another embodiment of the first aspect, when the electronic switch closes the shunt transitions to a high impedance state.

In another embodiment of the first aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the first aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the first aspect, the A/V recording and communication doorbell further includes a timer, wherein when the button is depressed the timer is activated and the electronic switch remains closed until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

Another embodiment of the first aspect further comprises the electronic switch opening when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the first aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, the method further comprising the electronic switch opening, the second timer being activated when the electronic switch opens, and the electronic switch being prevented from closing again until after the second timer expires.

Another embodiment of the first aspect further comprises the A/V recording and communication doorbell, in response to the button being depressed, sending an alert signal and a video signal to a network device, the video signal including images captured by the camera.

Another embodiment of the first aspect further comprises, when the power drawn from the AC power source is below the threshold power, the power manager directing a portion of the power drawn from the AC power source to the battery to charge the battery.

In a second aspect, an audio/video (A/V) recording and communication doorbell system is provided, the A/V recording and communication doorbell comprising an A/V recording and communication doorbell including a camera, a speaker, a microphone, a power manager, a battery, an AC/DC rectifier, and a DC/DC converter, wherein the A/V recording and communication doorbell is connected to an external AC power source through the AC/DC rectifier and the DC/DC converter; wherein the power manager is configured to draw power, up to a threshold power, from the AC power source, wherein the threshold power is measured at an output of the DC/DC converter; and when the power drawn from the AC power source reaches the threshold power, the power manager is further configured to draw supplemental power from the battery such that the power drawn from the AC power source never exceeds the threshold power as measured at the output of the DC/DC converter.

In an embodiment of the second aspect, the threshold power as measured at the output of the DC/DC converter is about 1.4 A.

In another embodiment of the second aspect, the A/V recording and communication doorbell further includes a button and an electronic switch, wherein when the button is depressed the electronic switch is configured to close, thereby diverting power from the AC power source away from the power manager.

In another embodiment of the second aspect, the A/V recording and communication doorbell is further configured such that when the electronic switch closes power from the AC power source is diverted through a signaling device to cause the signaling device to emit a sound.

Another embodiment of the second aspect further comprises a shunt, wherein the A/V recording and communication doorbell is further configured such that, prior to the electronic switch closing, the power drawn from the AC power source flows through the signaling device and the shunt connected in parallel with the signaling device.

In another embodiment of the second aspect, prior to the electronic switch closing the shunt is in a low impedance state.

In another embodiment of the second aspect, when the electronic switch closes the shunt transitions to a high impedance state.

In another embodiment of the second aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the second aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the second aspect, the A/V recording and communication doorbell further includes a timer, wherein the A/V recording and communication doorbell is further configured such that when the button is depressed the timer is activated and the electronic switch remains closed until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the second aspect, the electronic switch is configured to open when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the second aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, wherein the A/V recording and communication doorbell is further configured such that when the electronic switch opens the second timer is activated and the electronic switch is prevented from closing again until after the second timer expires.

In another embodiment of the second aspect, the A/V recording and communication doorbell is further configured to send, in response to the button being depressed, an alert signal and a video signal to a network device, the video signal including images captured by the camera.

In another embodiment of the second aspect, the A/V recording and communication doorbell is further configured such that when the power drawn from the AC power source is below the threshold power, the power manager directs a portion of the power drawn from the AC power source to the battery to charge the battery.

In a third aspect, a method for an audio/video (A/V) recording and communication doorbell system is provided, the A/V recording and communication doorbell including a camera, a speaker, a microphone, a button, and an electronic switch, wherein the A/V recording and communication doorbell is connected to an external power source, the method comprising the A/V recording and communication doorbell drawing power from the power source; the power flowing through a signaling device and a shunt connected in parallel with the signaling device, wherein the shunt is in a low impedance state; and when the button is depressed, the electronic switch closing and the shunt transitioning to a high impedance state, thereby diverting power from the power source through the signaling device to cause the signaling device to emit a sound.

In an embodiment of the third aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the third aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the third aspect, the A/V recording and communication doorbell further includes a timer, wherein when the button is depressed the timer is activated and the electronic switch remains closed until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

Another embodiment of the third aspect further comprises the electronic switch opening when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the third aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, the method further comprising the electronic switch opening, the second timer being activated when the electronic switch opens, and the electronic switch being prevented from closing again until after the second timer expires.

Another embodiment of the third aspect further comprises the A/V recording and communication doorbell, in response to the button being depressed, sending an alert signal and a video signal to a network device, the video signal including images captured by the camera.

In another embodiment of the third aspect, the A/V recording and communication doorbell further comprises a rechargeable battery.

Another embodiment of the third aspect further comprises, in response to the button being depressed, comparing a power level of the rechargeable battery to a threshold value.

Another embodiment of the third aspect further comprises the electronic switch closing only if the power level of the rechargeable battery is equal to or greater than the threshold value.

In a fourth aspect, an audio/video (A/V) recording and communication doorbell system is provided, comprising an A/V recording and communication doorbell including a camera, a speaker, a microphone, a button, and an electronic switch, wherein the A/V recording and communication doorbell is connected to an external power source; wherein the A/V recording and communication doorbell is configured to draw power from the power source such that the power flows through a signaling device and a shunt connected in parallel with the signaling device, wherein the shunt is in a low impedance state; and when the button is depressed, the electronic switch is configured to close, thereby transitioning the shunt to a high impedance state and diverting power from the power source through the signaling device to cause the signaling device to emit a sound.

In an embodiment of the fourth aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the fourth aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the fourth aspect, the A/V recording and communication doorbell further includes a timer, wherein the A/V recording and communication doorbell is further configured such that when the button is depressed the timer is activated and the electronic switch remains closed until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the fourth aspect, the electronic switch is configured to open when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the fourth aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, wherein the A/V recording and communication doorbell is further configured such that when the electronic switch opens the second timer is activated and the electronic switch is prevented from closing again until after the second timer expires.

In another embodiment of the fourth aspect, the A/V recording and communication doorbell is further configured to send, in response to the button being depressed, an alert signal and a video signal to a network device, the video signal including images captured by the camera.

In another embodiment of the fourth aspect, the A/V recording and communication doorbell further comprises a rechargeable battery.

In another embodiment of the fourth aspect, the A/V recording and communication doorbell is further configured to, in response to the button being depressed, compare a power level of the rechargeable battery to a threshold value.

In another embodiment of the fourth aspect, the A/V recording and communication doorbell is further configured to close the electronic switch only if the power level of the rechargeable battery is equal to or greater than the threshold value.

In a fifth aspect, an audio/video (A/V) recording and communication doorbell is provided, comprising a housing having an enclosure; a camera located at least partially within the enclosure; a speaker located at least partially within the enclosure; a microphone located at least partially within the enclosure; a button located at least partially within the enclosure and protruding outwardly from a front of the enclosure; and a shield located at the front of the enclosure; wherein the shield includes an upper portion that extends along the front of the enclosure above the button and a lower portion that extends along the front of the enclosure below the button; and wherein the camera is located behind the upper portion of the shield.

In an embodiment of the fifth aspect, the upper portion of the shield and the lower portion of the shield are separate pieces.

In another embodiment of the fifth aspect, the upper portion of the shield is transparent or translucent.

In another embodiment of the fifth aspect, the lower portion of the shield is transparent to infrared light, but partially or mostly opaque with respect to light in the visible spectrum.

Another embodiment of the fifth aspect further comprises a shell overlying the enclosure.

In another embodiment of the fifth aspect, the shell includes a recess that is sized and shaped to receive the enclosure in a close fitting engagement, such that outer surfaces of the enclosure abut conforming inner surfaces of the shell.

Another embodiment of the fifth aspect further comprises a back plate secured to a rear of the enclosure, wherein the back plate is sized and shaped such that edges of the back plate extend outward from edges of the enclosure, thereby creating a lip against which the shell abuts when the shell is mated with the enclosure.

In another embodiment of the fifth aspect, the shell includes a central opening in a front surface.

In another embodiment of the fifth aspect, the central opening is sized and shaped to accommodate the shield.

In another embodiment of the fifth aspect, the shield resides within the central opening of the shell such that a front surface of the shield is substantially flush with a front surface of the shell and there is little or no gap between outer edges of the shield and inner edges of the central opening in the shell.

In a sixth aspect, an audio/video (A/V) recording and communication doorbell is provided, comprising a housing having an enclosure; a camera located at least partially within the enclosure; a speaker located at least partially within the enclosure; a microphone located at least partially within the enclosure; a button located at least partially within the enclosure and protruding outwardly from a front of the enclosure; and a plurality of shells configured to overlie the enclosure; wherein each of the shells includes a recess that is sized and shaped to receive the enclosure in a close fitting engagement, such that outer surfaces of the enclosure abut conforming inner surfaces of each of the shells; and wherein each of the shells is a different color.

Another embodiment of the sixth aspect further comprises a shield located at the front of the enclosure.

In another embodiment of the sixth aspect, each of the shells includes a central opening in a front surface.

In another embodiment of the sixth aspect, the central opening is sized and shaped to accommodate the shield.

In another embodiment of the sixth aspect, the shield is configured to reside within the central opening of each of the shells such that a front surface of the shield is substantially flush with a front surface of each of the shells and there is little or no gap between outer edges of the shield and inner edges of the central opening in each of the shells.

In a seventh aspect, a method for an audio/video (A/V) recording and communication doorbell system, the A/V recording and communication doorbell including a camera, a speaker, a microphone, a button, and a means for diverting power, wherein the A/V recording and communication doorbell is connected to an external power source is provided, the method comprising: the A/V recording and communication doorbell drawing power from the power source; the power flowing through a signaling device and the power diverting means connected in parallel with the signaling device, wherein the power diverting means is in a low impedance state; and when the button is depressed, the power diverting means transitioning to a high impedance state, thereby diverting power from the power source through the signaling device to cause the signaling device to emit a sound.

In an embodiment of the seventh aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the seventh aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the seventh aspect, the A/V recording and communication doorbell further includes a timer, wherein when the button is depressed the timer is activated and the power diverting means remains in the high impedance state until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the seventh aspect, the method further comprises the power diverting means transitioning to the low impedance state when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the seventh aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, the method further comprising the power diverting means transitioning to the low impedance state, the second timer being activated when the power diverting means transitions to the low impedance state, and the power diverting means being prevented from again transitioning to the high impedance state until after the second timer expires.

In another embodiment of the seventh aspect, the method further comprises the A/V recording and communication doorbell, in response to the button being depressed, sending an alert signal and a video signal to a network device, the video signal including images captured by the camera.

In an eighth aspect, an audio/video (A/V) recording and communication doorbell system is provided, comprising: an A/V recording and communication doorbell including a camera, a speaker, a microphone, a button, and a power diverting means, wherein the A/V recording and communication doorbell is connected to an external power source; wherein the A/V recording and communication doorbell is configured to draw power from the power source such that the power flows through a signaling device and the power diverting means in parallel with the signaling device when the power diverting means is in a low impedance state; and when the button is depressed, the power diverting means is configured to transition to a high impedance state thereby diverting power from the power source through the signaling device to cause the signaling device to emit a sound.

In an embodiment of the eighth aspect, the signaling device is electro-mechanical or electronic.

In another embodiment of the eighth aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the eighth aspect, the A/V recording and communication doorbell further includes a timer, wherein the A/V recording and communication doorbell is further configured such that when the button is depressed the timer is activated and the power diverting means remains in the high impedance state until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the eighth aspect, the power diverting means is configured to transition to the low impedance state when the A/V recording and communication doorbell receives the notification that the call to the client device has been answered.

In another embodiment of the eighth aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, wherein the A/V recording and communication doorbell is further configured such that when the power diverting means transitions to the low impedance state, the second timer is activated and the power diverting means is prevented from again transitioning to the high impedance state until after the second timer expires.

In another embodiment of the eighth aspect, the A/V recording and communication doorbell is further configured to send, in response to the button being depressed, an alert signal and a video signal to a network device, the video signal including images captured by the camera.

In a ninth aspect, an audio/video (A/V) recording and communication doorbell system is provided, comprising: a power diverting means; and an A/V recording and communication doorbell including a camera, a speaker, a microphone, and a button, wherein the A/V recording and communication doorbell is connected to an external power source; wherein the A/V recording and communication doorbell is configured to draw power from the power source such that the power flows through a signaling device and the power diverting means in parallel with the signaling device when the power diverting means is in a low impedance state; and when the button is depressed, the power diverting means is configured to transition to a high impedance state, thereby diverting power from the power source through the signaling device to cause the signaling device to emit a sound.

In an embodiment of the ninth aspect, the power diverting means is at least one of external to and internal to the A/V recording and communication doorbell.

In another embodiment of the ninth aspect, the power diverting means includes at least one component external to the A/V recording and communication doorbell and at least one component internal to the A/V recording and communication doorbell.

In another embodiment of the ninth aspect, the signaling device is external to the A/V recording and communication doorbell.

In another embodiment of the ninth aspect, the A/V recording and communication doorbell further includes a timer, wherein when the button is depressed the timer is configured to be activated and the power diverting means is configured to remain in the high impedance state until the timer expires, unless the A/V recording and communication doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the ninth aspect, the timer is a first timer and the A/V recording and communication doorbell further includes a second timer, and wherein the power diverting means is further configured to transition to the low impedance state, the second timer being activated when the power diverting means transitions to the low impedance state, and the power diverting means being prevented from again transitioning to the high impedance state until after the second timer expires.

In a tenth aspect, an audio/video recording and communication doorbell (A/V doorbell) system is provided, the system comprising: an A/V doorbell comprising a camera, a speaker, a microphone, and a button, wherein the A/V doorbell is configured to draw power from an external power source; and an electronic device configured for connection in parallel across a doorbell signaling device, wherein the electronic device includes a low-impedance state and a high-impedance state; wherein the A/V doorbell is configured to draw power from the external power source through the electronic device when the electronic device is in the low-impedance state; and wherein the electronic device is configured to transition from the low-impedance state to the high-impedance state when the button is depressed, thereby diverting power drawn from the external power source away from the electronic device.

In an embodiment of the tenth aspect, the A/V doorbell further comprises a switch having an open position and a closed position.

In another embodiment of the tenth aspect, when the button is depressed, the switch transitions from the open position to the closed position.

In another embodiment of the tenth aspect, the electronic device is in the low-impedance state when the switch is in the open position and is in the high-impedance state when the switch is in the closed position.

In another embodiment of the tenth aspect, the switch is a first switch, and wherein the electronic device comprises a second switch having an open position and a closed position.

In another embodiment of the tenth aspect, the electronic device is in the low-impedance state when the second switch is in the closed position and is in the high-impedance state when the second switch is in the open position.

In another embodiment of the tenth aspect, when the first switch transitions from the open position to the closed position, the second switch transitions from the closed position to the open position.

In another embodiment of the tenth aspect, the when the second switch transitions from the closed position to the open position, the electronic device transitions from the low-impedance state to the high-impedance state.

In another embodiment of the tenth aspect, the electronic device further comprises a rectifier, a diode, and a resistor, and wherein when the first switch transitions from the open position to the closed position, the rectifier outputs a voltage such that the diode biased by the resistor conducts enough current to cause the second switch to transition from the closed position to the open position.

In another embodiment of the tenth aspect, the electronic device further comprises a first comparator circuit that returns the second switch to the closed position, when the first switch is in the open position.

In another embodiment of the tenth aspect, the electronic device further comprises a second comparator circuit that returns the second switch to the closed position, in the event that the first comparator circuit fails.

In another embodiment of the tenth aspect, the A/V doorbell further comprises a timer that is activated when the button is depressed and the electronic device is configured to remain in the high-impedance state until the timer expires.

In another embodiment of the tenth aspect, the timer is a first timer, and wherein the A/V doorbell further includes a second timer that is activated when the electronic device transitions to the low-impedance state, and the electronic device is prevented from transitioning to the high-impedance state until after the second timer expires.

In another embodiment of the tenth aspect, the electronic device transitions to the low-impedance state when the A/V doorbell receives a notification that a call to a client device has been answered.

In another embodiment of the tenth aspect, the high-impedance state has a resistance greater than 1K ohms.

In another embodiment of the tenth aspect, the electronic device is internal to the A/V doorbell.

In another embodiment of the tenth aspect, the doorbell signaling device is external to the A/V doorbell.

In another embodiment of the tenth aspect, the power drawn from the external power source is diverted through the doorbell signaling device causing the doorbell signaling device to emit a sound.

In another embodiment of the tenth aspect, the doorbell signaling device emits the sound when the power drawn from the external power source diverted through the doorbell signaling device is above a threshold.

The above description presents the best mode contemplated for carrying out the present embodiments, and of the manner and process of practicing them, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which they pertain to practice these embodiments. The present embodiments are, however, susceptible to modifications and alternate constructions from those discussed above that are fully equivalent. Consequently, the present invention is not limited to the particular embodiments disclosed. On the contrary, the present invention covers all modifications and alternate constructions coming within the spirit and scope of the present disclosure. For example, the steps in the processes described herein need not be performed in the same order as they have been presented, and may be performed in any order(s). Further, steps that have been presented as being performed separately may in alternative embodiments be performed concurrently. Likewise, steps that have been presented as being performed concurrently may in alternative embodiments be performed separately. 

What is claimed is:
 1. A method for an audio/video (A/V) recording and communication doorbell system including an A/V recording and communication doorbell, the A/V recording and communication doorbell including a camera, a speaker, a microphone, and a button, the method comprising: the A/V recording and communication doorbell drawing power from an external power source; the power flowing through an electronic device associated with a signaling device, wherein the electronic device is in a low impedance state; and when the button is depressed, the electronic device transitioning to a high impedance state, thereby diverting power from the power source through the external signaling device to cause the signaling device to sound.
 2. The method of claim 1, wherein a switch of the electronic device is closed when the electronic device is in the low impedance state.
 3. The method of claim 2, wherein the switch of the electronic device is open when the electronic device is in the high impedance state.
 4. The method of claim 3, further comprising the electronic device sensing voltage across first and second terminals of the electronic device.
 5. The method of claim 4, further comprising the electronic device opening the switch in response to sensing the voltage across the first and second terminals of the electronic device.
 6. The method of claim 3, further comprising the electronic device using power from the external power source to open the switch.
 7. The method of claim 6, further comprising the electronic device converting alternating current (AC) from the external power source to direct current (DC) to open the switch.
 8. The method of claim 1, further comprising the electronic device sensing voltage across first and second terminals of the electronic device.
 9. The method of claim 8, further comprising the electronic device transitioning to the high impedance state in response to sensing the voltage across the first and second terminals of the electronic device.
 10. The method of claim 1, further comprising the power flowing through a resistor of the electronic device when the electronic device is in a low impedance state.
 11. A method for an audio/video (A/V) recording and communication doorbell system including an A/V recording and communication doorbell, the A/V recording and communication doorbell including a camera, a speaker, a microphone, and a button, the method comprising: an electronic device in a low impedance state diverting power from an external power source away from a signaling device and to the A/V recording and communication doorbell; and when the button is depressed, the electronic device transitioning to a high impedance state, thereby diverting power from the external power source through the signaling device to cause the signaling device to sound.
 12. The method of claim 11, wherein a switch of the electronic device is closed when the electronic device is in the low impedance state.
 13. The method of claim 12, wherein the switch of the electronic device is open when the electronic device is in the high impedance state.
 14. The method of claim 13, further comprising the electronic device sensing voltage across first and second terminals of the electronic device.
 15. The method of claim 14, further comprising the electronic device opening the switch in response to sensing the voltage across the first and second terminals of the electronic device.
 16. The method of claim 13, further comprising the electronic device using power from the external power source to open the switch.
 17. The method of claim 16, further comprising the electronic device converting alternating current (AC) from the external power source to direct current (DC) to open the switch.
 18. The method of claim 11, further comprising the electronic device sensing voltage across first and second terminals of the electronic device.
 19. The method of claim 18, further comprising the electronic device transitioning to the high impedance state in response to sensing the voltage across the first and second terminals of the electronic device.
 20. The method of claim 11, further comprising the power flowing through a resistor of the electronic device when the electronic device is in a low impedance state. 